ORIGIN OF THE CEREBRAL NERVES. 511 



with those of the anterior division of the pons. These clusters 

 are immediately connected with disintegrated plexiform por- 

 tions of the stratum zonale contained in the pyramids; and 

 it would appear, therefore, that the connections of the anterior 

 crus-cerebri tract of the hypoglossus is effected by the small 

 anterior pons covering the pyramids. 



These fasciculi of the crus-cerebri form a contorted knot-like 

 mass in the hypoglossal nuclei, through which they run to 

 reach the rootlets of that nerve. The central extremity of the 

 glomerulus projects from the raphe' through the most posterior 

 fibrse arcuatse, forming a continuation of the above-described 

 fibrse rectse. After these fibrse arcuatse have, as they run along 

 their external border, successively entered each of the two 

 hypoglossal nuclei, and united themselves with the multicaudate 

 nerve corpuscles, they penetrate along the inner border of the, 

 nuclei into the hypoglossal rootlets, which for the most part 

 emerge between the pyramids and the olivary bodies, but in 

 part also through the olivary bodies themselves. The fact that 

 such traversing fasciculi not unfrequently terminate abruptly 

 in the interior of the olivary body has led Lenhossek and 

 Schroder v. d. Kolk to adopt the erroneous view of a partial 

 connection of the hypoglossal nerve with the olivary body 

 through a pedunculus olivse. 



All observers and amongst the most recent, Gerlach admit 

 also a direct origin for the hypoglossal fasciculi from the crus 

 cerebri through the raphe, the fibres of which, forming the 



root of the fifth) ; G, gelatinous substance, with transverse section of 

 the medulla of the ascending roots of the fifth ; Z, zonular layer, 

 forming posteriorly the most inferior remains of the restiform body ; 

 H, posterior column of the medulla oblongata, with the nuclei of the 

 cuneate column (Cn) and of the slender fasciculus (Gr) ; Oe and Oi, 

 external and internal accessory olivary bodies ; E, raphe ; MFJ, 

 MFE, internal and external division of the transverse section of the 

 motor area (anterior and lateral columns) ; xn 1 and xn', internal and 

 external convolute of the hypoglossal nucleus ; xn, root of the hypo- 

 glossal ; xi, root of the accessorius ; xi 1 , nucleus of the accessory ; 

 xi 2 , a nucleus of the accessory nerve which is connected with the 

 commissure running in the bolt (Biegel) (06) ; W, the ascending root 

 of the lateral mixed system ; A 8, fibrse arcuatse. 



